Method for estimating surface moisture content of wood chips

Abstract

A method for estimating surface moisture content of wood chips for use in a pulp and paper production process comprises measuring chip surface moisture using an infrared surface moisture sensor, and adjusting a calibration of the surface moisture measured with a model using values of a set of optical parameters representing light reflection characteristics of the wood chips, to estimate their surface moisture content.

1. A method for estimating surface moisture content of wood chips comprising the steps of:
 i) measuring chip surface moisture using an infrared surface moisture sensor; and 
 ii) adjusting calibration of the surface moisture measured at said step i) with a model using values of a set of optical parameters representing light reflection characteristics of said wood chips, to estimate said surface moisture content. 
 
     
     
       2. The method according to  claim 1 , wherein said infrared surface moisture sensor is a near-infrared surface moisture sensor. 
     
     
       3. The method according to  claim 2 , wherein said optical parameter values include color image pixel data that are obtained using an optical inspection technique including the steps of:
 a) directing polychromatic light onto an inspected area of said wood chips; and 
 b) sensing light reflected from said inspected area to generate said color image pixel data representing values of color components within one or more color spaces for pixels forming an image of said inspected area. 
 
     
     
       4. The method according to  claim 3 , wherein said model is defined by:
     M=a   1   M   M   +a   2   H+a   3   S+a   4   L+a   5   K+C   
 
       wherein:
 M is said chip surface moisture content; 
 M M  is said measured moisture; 
 H, S, L are said color components within one said color space; 
 K is chip darkness; 
 a 1  to a 5  predetermined coefficients; and 
 C is a predetermined constant.